Ruby on Rails, ActionCable, Messages don't show up

I've implemented ActionCable in the past before school got busy, and not without some trouble then--and now it is causing me trouble yet again. I reach 17:00mins in that video with no problem, and everything makes sense--however when I send in the command it does not bring up any message.

So, what I do see:

"hello world" is showing up, but not any given input (not even upon reloading the page)

First in my terminal:

Started GET "/cable" for ::1 at 2016-05-23 21:45:00 -0600

Started GET "/cable/" [WebSocket] for ::1 at 2016-05-23 21:45:00 -0600

I could post some code, I should post some code, but I am fairly sure that all of my code follows the video. I'll be sorting through it for awhile still, I'm just more looking for any tips/insight/help for other ideas/things to check. I've had a similar problem before in my previous attempts of implementing ActionCable, where the messages will even be sent in and processed, but not showing up until reloading the web page.

Thank you for any help,

... okay, I guess I better put some code first:

javascripts/channels/room.coffee

App.room = App.cable.subscriptions.create "RoomChannel",
# Called when the subscription is ready for use on the server
connected: ->

# Called when the subscription has been terminated by the server
disconnected: ->

# Called when there's incoming data on the websocket for this channel
received: (data) ->
$('#messages').append "<div>#{data}</div>"

Array values in the parameter to `Gem.paths=` are deprecated.
Please use a String or nil.
An Array ({"GEM_PATH"=>["/Users/Kegan/.rvm/gems/ruby-2.3.1", "/Users/Kegan/.rvm/gems/ruby-2.3.1@global"]}) was passed in from bin/rails:3:in `load'
=> Booting Puma
=> Rails 5.0.0.rc1 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
[Simple Form] Simple Form is not configured in the application and will use the default values. Use `rails generate simple_form:install` to generate the Simple Form configuration.
Puma starting in single mode...
* Version 3.4.0 (ruby 2.3.1-p112), codename:
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://localhost:3000
Use Ctrl-C to stop